One of the common trends in the electronics industry is the miniaturization of electronic devices. This is especially true for electronic devices operated through the use of semiconductor microchips. Microchips are commonly viewed as the brains of most electronic devices. In general, a microchip comprises a small silicon wafer upon which can be built millions or billions of nanoscopic electronic devices that are integrally configured to form electronic circuits. The circuits are interconnected in a unique way to perform a desired function.
With the desire to make high density microchips, it is necessary to decrease the size of the individual electronic devices and interconnects thereon. This movement also known as the so called “scale down” movement has increased the number and complexity of circuits on a single microchip.
Conventionally, electronic devices are formed side-by-side in a single plane on a common substrate, such as a silicon wafer. This side-by-side positioning, however, uses a relatively large amount of surface area, or “real estate,” on the substrate. As a result, devices may be formed vertically in an effort to utilize less substrate area. In order to be competitive, such vertical devices are formed with high aspect ratios (i.e., the ratio of height to widths). However, as the aspect ratio of a device increases, it becomes increasingly difficult to satisfy both territory and electronic requirements of the corresponding interconnects. For this reason, simpler planar device scale downs dominate the industry in real practice to date.
A recent trend is to vertically stack semiconductor devices on a substrate. However, the stacking of semiconductor devices adds an additional complexity to connecting the components of the semiconductor device as well as providing efficient interconnects between the stacks.
Accordingly, there is a need for a method of forming a vertical semiconductor device which provides for competitive accessibility of interconnects to an electronic device in a stacked semiconductor device.